FIG. 1 is a view showing the structure of a compression line spring.
Generally, the compression line spring 10 is a spring that is manufactured by spirally winding a linear spring material. The compression line spring is processed through a seat-surface grinding process so that seat surfaces 10a and 10b formed on opposite ends of the compression line spring 10 are oriented perpendicular to a shaft S of the spring 10.
Meanwhile, an apparatus for grinding coil springs was proposed in Japanese Utility Model Registration No. Sho. 46-8789.
FIG. 2 illustrates the construction of the apparatus for grinding coil springs.
The conventional grinding apparatus includes two chains 2 and 4 that are respectively disposed at upper and lower positions, and each of which includes a plurality of supports 5, and whetstones 11 that are disposed on opposite sides of the chains 2 and 4 to grind the opposite ends of the coil springs.
In the conventional grinding apparatus, coil springs are seated on the supports provided in the lower chain, and the coil springs are compressed and fixed in place by the supports provided in the upper chain. Thereafter, the coil springs are moved through the whetstones, whereby seat surfaces formed on the coil springs are ground.
Meanwhile, a V-shaped depression is formed in each of the supports of the upper and lower chains so that the corresponding coil spring can be stably supported by the supports.
However, in the case where two supports each having a V-shaped depression are disposed at upper and lower positions facing each other with a coil spring interposed therebetween, the coil spring may not be stably supported by the supports unless the two supports are accurately aligned with each other.
Therefore, it is required for the conventional grinding apparatus to be precisely processed and set such that the two supports disposed at upper and lower positions facing each other are accurately aligned with each other with a coil spring interposed therebetween. Thus, it is not easy to manufacture, use, and maintain the apparatus.